Merge pull request #17053 from yashykt/global_interceptor

Add global client interceptor factory

4 files changed, 36 insertions, 5 deletions

diff --git a/include/grpcpp/channel.h b/include/grpcpp/channel.h
index 14209b85ee..4502b94b17 100644
--- a/include/grpcpp/channel.h
+++ b/include/grpcpp/channel.h
@@ -91,7 +91,7 @@ class Channel final : public ChannelInterface,
 
   internal::Call CreateCallInternal(const internal::RpcMethod& method,
                                     ClientContext* context, CompletionQueue* cq,
-                                    int interceptor_pos) override;
+                                    size_t interceptor_pos) override;
 
   const grpc::string host_;
   grpc_channel* const c_channel_;  // owned
diff --git a/include/grpcpp/impl/codegen/channel_interface.h b/include/grpcpp/impl/codegen/channel_interface.h
index 39805a0ef5..6ec1ffb8c7 100644
--- a/include/grpcpp/impl/codegen/channel_interface.h
+++ b/include/grpcpp/impl/codegen/channel_interface.h
@@ -134,7 +134,7 @@ class ChannelInterface {
   virtual internal::Call CreateCallInternal(const internal::RpcMethod& method,
                                             ClientContext* context,
                                             CompletionQueue* cq,
-                                            int interceptor_pos) {
+                                            size_t interceptor_pos) {
     return internal::Call();
   }
 
diff --git a/include/grpcpp/impl/codegen/client_interceptor.h b/include/grpcpp/impl/codegen/client_interceptor.h
index 0e08a7ce01..f69c99ab22 100644
--- a/include/grpcpp/impl/codegen/client_interceptor.h
+++ b/include/grpcpp/impl/codegen/client_interceptor.h
@@ -19,6 +19,7 @@
 #ifndef GRPCPP_IMPL_CODEGEN_CLIENT_INTERCEPTOR_H
 #define GRPCPP_IMPL_CODEGEN_CLIENT_INTERCEPTOR_H
 
+#include <memory>
 #include <vector>
 
 #include <grpcpp/impl/codegen/interceptor.h>
@@ -41,7 +42,14 @@ class ClientInterceptorFactoryInterface {
   virtual ~ClientInterceptorFactoryInterface() {}
   virtual Interceptor* CreateClientInterceptor(ClientRpcInfo* info) = 0;
 };
+}  // namespace experimental
 
+namespace internal {
+extern experimental::ClientInterceptorFactoryInterface*
+    g_global_client_interceptor_factory;
+}
+
+namespace experimental {
 class ClientRpcInfo {
  public:
   ClientRpcInfo() {}
@@ -71,12 +79,21 @@ class ClientRpcInfo {
   void RegisterInterceptors(
       const std::vector<std::unique_ptr<
           experimental::ClientInterceptorFactoryInterface>>& creators,
-      int interceptor_pos) {
+      size_t interceptor_pos) {
+    if (interceptor_pos > creators.size()) {
+      // No interceptors to register
+      return;
+    }
     for (auto it = creators.begin() + interceptor_pos; it != creators.end();
          ++it) {
       interceptors_.push_back(std::unique_ptr<experimental::Interceptor>(
           (*it)->CreateClientInterceptor(this)));
     }
+    if (internal::g_global_client_interceptor_factory != nullptr) {
+      interceptors_.push_back(std::unique_ptr<experimental::Interceptor>(
+          internal::g_global_client_interceptor_factory
+              ->CreateClientInterceptor(this)));
+    }
   }
 
   grpc::ClientContext* ctx_ = nullptr;
@@ -90,6 +107,20 @@ class ClientRpcInfo {
   friend class grpc::ClientContext;
 };
 
+// PLEASE DO NOT USE THIS. ALWAYS PREFER PER CHANNEL INTERCEPTORS OVER A GLOBAL
+// INTERCEPTOR. IF USAGE IS ABSOLUTELY NECESSARY, PLEASE READ THE SAFETY NOTES.
+// Registers a global client interceptor factory object, which is used for all
+// RPCs made in this process.  If the argument is nullptr, the global
+// interceptor factory is deregistered. The application is responsible for
+// maintaining the life of the object while gRPC operations are in progress. It
+// is unsafe to try to register/deregister if any gRPC operation is in progress.
+// For safety, it is in the best interests of the developer to register the
+// global interceptor factory once at the start of the process before any gRPC
+// operations have begun. Deregistration is optional since gRPC does not
+// maintain any references to the object.
+void RegisterGlobalClientInterceptorFactory(
+    ClientInterceptorFactoryInterface* factory);
+
 }  // namespace experimental
 }  // namespace grpc
 
diff --git a/include/grpcpp/impl/codegen/intercepted_channel.h b/include/grpcpp/impl/codegen/intercepted_channel.h
index 612e56d862..5255a6d147 100644
--- a/include/grpcpp/impl/codegen/intercepted_channel.h
+++ b/include/grpcpp/impl/codegen/intercepted_channel.h
@@ -42,7 +42,7 @@ class InterceptedChannel : public ChannelInterface {
   }
 
  private:
-  InterceptedChannel(ChannelInterface* channel, int pos)
+  InterceptedChannel(ChannelInterface* channel, size_t pos)
       : channel_(channel), interceptor_pos_(pos) {}
 
   Call CreateCall(const RpcMethod& method, ClientContext* context,
@@ -70,7 +70,7 @@ class InterceptedChannel : public ChannelInterface {
   CompletionQueue* CallbackCQ() override { return channel_->CallbackCQ(); }
 
   ChannelInterface* channel_;
-  int interceptor_pos_;
+  size_t interceptor_pos_;
 
   friend class InterceptorBatchMethodsImpl;
 };